我国近46年来的寒潮时空变化与冬季增暖

使用中国气象局资料中心整编的572个站点1960年1月1日到2005年12月31日日最低温度、日平均气压、日平均风速和北极涛动(AO) 指数等气象要素，从一个新的角度分析了我国寒潮时空变化与冬季增暖的联系。寒潮爆发以降温、升压和大风天气为主要特征。定义1日和2日降温达到10℃以上的降温事件为寒潮，大于20℃为极端寒潮。发生在我国的寒潮以北方(35°N以北)最多，其次是中国东部的江南地区。东北的寒潮始于10月，而河套和江南的寒潮在4月份比较频繁。把10月到次年4月寒潮频繁活动的时段确定为冬季风时期。在所有的降温事件中，只有不到1/3的事件伴随有升压和大风天气。过去的45个冬季风期间，寒潮和极端寒潮事件普遍减少，我国新疆、华北、东北和华东减少最为显著，减少的最大幅度达到1～2次/10 a。降温事件、升压频次和大风频次也都在减少。AO指数升高表征了西风带上天气尺度斜压波动的减少和减弱，从而导致我国中高纬度寒潮事件的减少。降温频次的减少在一定程度上导致了冬季最低温度平均值的升高，形成了持续的暖冬。     

Relationship between Solar Wind-Magnetosphere Energy and Eurasian Winter Cold Events

The profound impact of solar irradiance variations on the decadal variability of Earth' s climate has been investigated by previous studies.However,it remains a challenge to quantify the energetic particle precipitation(EPP) influence on the surface climate,which is an emerging research topic.The solar wind is a source of magnetospheric EPP,and the total energy input from the solar wind into Earth' s magnetosphere(E_(in)) shows remarkable interdecadal and interannual variability.B ased on the new E_(in) index,this study reveals a significant interannual relationship between the annual mean E_(in)and Eurasian cold extremes in the subsequent winter.Less frequent cold events are observed over Eurasia(primarily north of 50°N) following the higher-than-normal E_(in) activity in the previous year,accompanied by more frequent cold events over northern Africa,and vice versa.This response pattern shows great resemblance to the first empirical orthogonal function of the variability of cold extremes over Eurasia,with a spatial correlation coefficient of 0.79.The pronounced intensification of the positive North Atlantic Oscillation events and poleward shift of the North Atlantic storm track associated with the anomalously higher E_(in) favor the anomalous extreme atmospheric circulation events,and thus less frequent extreme cold temperatures over northern Eurasia on the interannual time scale.It is further hypothesized that the wave-mean flow interaction in the stratosphere and troposphere is favorable for the connection of E_(in) signals to tropospheric circulation and climate in the following winter.     

近40年海南岛冷冬气候特征及其成因分析

利用海南岛17个市、县近40年气象观测站逐月气温观测资料,参照《暖冬等级》国家标准,对海南岛异常冷冬事件的时空分布规律进行了分析。在此基础上,利用国家气候中心提供的74项环流指数以及1977—2017年NCEP/NCAR全球再分析格点资料、NOAA ERSST全球海表温度格点资料以及Nino3. 4指数和AO指数,对海南岛冷冬事件形成机制进行了研究。结果表明:海南岛冬季平均气温存在明显的年代际变化特征,近40年海南岛冷冬频发,共出现12次冷冬年。南部市、县发生冷冬的频次大于中部及北部,北部市、县冷冬发生的强度强于南部。海南岛冷冬形成原因主要是对流层大气环流异常,西伯利亚高压增强,东亚冬季风显著偏强,对应副热带高压偏弱、位置偏东,影响海南岛的冷空气更加活跃,使得海南岛冬季气温偏低。另外,南海海温较常年偏低,ENSO冷位相叠加AO指数正位相,有利于进一步诱发大气环流异常,促使海南岛冬季气温偏低,出现异常冷冬事件。     

全球夏、冬季加热场的气候学特征及其年代际变化

利用NCEP/NCAR再分析资料,计算了1948-2002年全球夏、冬季节大气热源的气候分布,并对其年代际变化规律进行分析.研究表明,全球存在4个主要的大气热源中心,其位置随季节的改变而改变.夏季分别位于中非、孟加拉湾附近、热带西太平洋菲律宾群岛附近及加勒比海西南部;冬季则移至南非、海洋大陆至印度洋一带、澳大利亚西北部至南太平洋一带及南美洲北部.夏季中非、热带西太平洋菲律宾群岛附近及加勒比海西南部大气热源都表现出明显的年代际变化特征,中非热源在20世纪70年代存在减弱突变,而热带西太平洋菲律宾群岛和加勒比海西南部热源存在增强突变,孟加拉湾热源强度存在减弱变化趋势.冬季南美洲北部热源具有明显的年代际变化,在70年代中期存在增强突变,南非和海洋大陆至印度洋一带热源强度存在增强变化趋势,而澳大利亚西北至南太平洋一带热源强度存在减弱变化趋势.     

An Isentropic Mass Circulation View on the Extreme Cold Events in the 2020/21 Winter

Three extreme cold events successively occurred across East Asia and North America in the 2020/21 winter.This study investigates the underlying mechanisms of these record-breaking persistent cold events from the isentropic mass circulation(IMC)perspective.Results show that the midlatitude cold surface temperature anomalies always co-occurred with the high-latitude warm anomalies,and this was closely related to the strengthening of the low-level equatorward cold air branch of the IMC,particularly along the climatological cold air routes over East Asia and North America.Specifically,the two cold surges over East Asia in early winter were results of intensification of cold air transport there,influenced by the Arctic sea ice loss in autumn.The weakened cold air transport over North America associated with warmer northeastern Pacific sea surface temperatures(SSTs)explained the concurrent anomalous warmth there.This enhanced a wavenumber-1 pattern and upward wave propagation,inducing a simultaneous and long-lasting stronger poleward warm air branch(WB)of the IMC in the stratosphere and hence a displacement-type Stratospheric Sudden Warming(SSW)event on 4 January.The WB-induced increase in the air mass transported into the polar stratosphere was followed by intensification of the equatorward cold branch,hence promoting the occurrence of two extreme cold events respectively over East Asia in the beginning of January and over North America in February.Results do not yield a robust direct linkage from La Ni?a to the SSW event,IMC changes,and cold events,though the extratropical warm SSTs are found to contribute to the February cold surge in North America.     

抚顺冬季异常偏冷年气候特征及成因分析

利用抚顺气象观测站气象资料,分析了抚顺冬季异常偏冷年的气候特征,发现异常偏冷年都有最低气温低于-30℃的冷段,并且气候变暖后,降雪多、积雪深是其主要特征。同时通过分析深层平均地温、太阳黑子活动、大气环流等资料,发现抚顺冬季气温异常偏低一般都出现在太阳黑子峰谷年附近,并与前期3-11月0．8m深层平均地温呈正相关,北半球500hPa冬季欧亚地区距平场为西高东低,东亚槽稳定建立,并且大气环流以大西洋-欧亚E型环流型为主。     

A Technique for Estimating Polar Ozone Loss: Results for the Northern 1991/92 Winter Using EASOE Data

In this paper we describe a technique for estimating chemical ozone loss in the Arctic vortex. Observed ozone and temperature profiles are combined with the model potential vorticity field to produce time series of vortex averaged ozone mixing ratios on chosen isentropic surfaces. Model-derived radiative heating rates and observed vertical gradients of ozone are then used to estimate the change in ozone that would occur due to diabatic descent. Discrepancies with the observed ozone are interpreted as being of chemical origin, assuming that there is negligible horizontal transport or mixing of air into the vortex. The technique is illustrated using ozone sonde measurements collected during the 1991/92 European Arctic Stratospheric Ozone Experiment (EASOE), meteorological analyses from the European Centre for Medium-range Weather Forecasts (ECMWF) and radiative heating rates extracted from the Global Atmospheric Modelling Programme (UGAMP) 3D General Circulation Model. Our results show that there was photochemical ozone destruction inside the Arctic vortex in early 1992 with a loss between 475 K and 550 K (around 20 km) of 0.32±0.15 ppmv in the first 20 days of January, equivalent to a rate of 0.51±0.24%/day (at the 95% confidence level).     

冬季全国性持续低温事件过程中的平流层—对流层相互作用

利用1959～2017年ERA40/ERA-Interim逐日再分析资料和国家气候中心的逐日站点资料,针对发生在当年11月至次年3月(NDJFM)的全国性持续低温事件(EPECEs),分析了热带外环流的变化特征,以及平流层—对流层相互作用.结果 表明,全国性EPECEs可划分为冷空气在乌拉尔山—西伯利亚关键区堆积和冷空...     

基于MaxEnt模型的四川省冬小麦气候适宜性区划

基于2019年四川省97个县市区冬小麦的种植信息,以及1980~2021年159个气象站数据,选取影响冬小麦种植分布的13个潜在气候影响因子,结合最大熵模型（MaxEnt）,构建了冬小麦种植分布和气候因子的关系模型。结果表明：主导气候因子贡献率大小的为年日照时数＞1月平均气温＞年平均低温＞年降水量＞年相对湿度;冬小麦的潜在适宜区主要分布在99°E以东,26°~33°N区域;未来气候背景下,大部分市州总适宜区面积无明显变化。     

Extreme Cold Events from East Asia to North America in Winter 2020/21: Comparisons,Causes, and Future Implications

Three striking and impactful extreme cold weather events successively occurred across East Asia and North America during the mid-winter of 2020/21.These events open a new window to detect possible underlying physical processes.The analysis here indicates that the occurrences of the three events resulted from integrated effects of a concurrence of anomalous thermal conditions in three oceans and interactive Arctic-lower latitude atmospheric circulation processes,which were linked and influenced by one major sudden stratospheric warming(SSW).The North Atlantic warm blob initiated an increased poleward transient eddy heat flux,reducing the Barents-Kara seas sea ice over a warmed ocean and disrupting the stratospheric polar vortex(SPV)to induce the major SSW.The Rossby wave trains excited by the North Atlantic warm blob and the tropical Pacific La Nina interacted with the Arctic tropospheric circulation anomalies or the tropospheric polar vortex to provide dynamic settings,steering cold polar air outbreaks.The long memory of the retreated sea ice with the underlying warm ocean and the amplified tropospheric blocking highs from the midlatitudes to the Arctic intermittently fueled the increased transient eddy heat flux to sustain the SSW over a long time period.The displaced or split SPV centers associated with the SSW played crucial roles in substantially intensifying the tropospheric circulation anomalies and moving the jet stream to the far south to cause cold air outbreaks to a rarely observed extreme state.The results have significant implications for increasing prediction skill and improving policy decision making to enhance resilience in“One Health,One Future”.     

A Possible Mechanism for Winter Sea Ice Decline over the Bering Sea and Its Relationship with Cold Events over North America

In this study, the mechanism for the sea ice decline over the Bering Sea and its relationship with cold events over North America are investigated based on the daily ERA-Interim data during the winter(December–February) of1979–2016. The results show that the sea ice decline over western(eastern) Bering Sea is mainly contributed by(1)the strengthened southerly(southeasterly) wind near the surface, which possibly pushes the sea ice to move northward, and(2) the intensified downward infrared radiation(IR), which is closely related to the local increasing surface air temperature(SAT) and the intensified moisture convergence mostly induced by the anomalous southeasterly wind associated with an anticyclonic anomaly over the Alaska Bay. During the sea ice decline over the Bering Sea, a cold SAT anomaly is simultaneously found over North America. It is proved that the occurrence of such a cold event is driven by the atmospheric internal variation, but not the forcing of sea ice decline over the Bering Sea. This study deepens our understanding of sea ice decline and its relationship with contemporary cold events in winter.     

广西冬季严重冻害的前期强信号及预测概念模型

利用500hPa高度场、北太平洋海温场、青藏高原积雪以及表征大气活动特征的物理量等资料,从多方面较为系统地研究广西冬季严重冻害的前期强信号,最后形成预测概念模型,为广西冬季严重冻害的预测提供多方面的信息。     

北半球冬季平流层强、弱极涡事件演变过程的对比分析

利用1958～2017年逐日的NCEP/NCAR再分析资料对北半球冬季平流层强、弱极涡事件的演变过程进行了对比分析,同时比较了有平流层爆发性增温（SSW）和无SSW发生的两类弱极涡事件的环流演变和动力学特征。结果表明,强极涡的形成存在着缓慢发展和快速增强的过程,而弱极涡事件的建立非常迅速;和强极涡事件相比,弱极涡事件的峰值强度更强,异常中心的位置更高。此外,强、弱极涡事件的产生与波流相互作用的正反馈过程密切相关。对于强极涡事件,发展阶段的太平洋—北美（PNA）型异常削弱了行星波一波;当平流层西风达到一定强度,上传的行星波受到强烈抑制,使得极涡迅速增强达到峰值。而对于弱极涡事件,发展阶段一波型的异常增强了行星波上传,通过对纬向流的拖曳作用使得平流层很快处于弱西风状态,更多行星波进入平流层导致极涡急剧减弱甚至崩溃。针对有、无SSW发生的两类弱极涡事件的对比分析表明,有SSW发生的弱极涡事件发展阶段,平流层出现强的向上的一波Eliassen-Palm（EP）通量异常,通过正反馈过程使得一波和二波上传同时增强而导致极涡崩溃;无SSW发生的弱极涡事件发展阶段,平流层缺乏向上的一波通量,二波活动起到重要作用,其总的行星波上传远弱于有SSW发生的弱极涡事件。对于无SSW发生的弱极涡事件,其发展和成熟阶段对流层上部出现类似欧亚（EU）型的高度异常,伴随着强的向极的EP通量异常,导致对流层有极强的负北极涛动（AO）型异常。而有SSW发生的弱极涡事件发展阶段对流层上部主要表现为北太平洋上空来自低纬的波列异常,其后期的对流层效应更加滞后也不连续,对流层AO异常的强度明显弱于无SSW发生的弱极涡事件。     

海南雷暴气候特征及大气环流背景分析

利用1966～2005年海南地区18个市、县逐日雷暴观测资料及NECP再分析资料和EOF分析方法,分析了海南地区雷暴天气的气候特征及其气候变化的可能影响因素.结果表明:海南雷暴的年际变化呈较明显的下降趋势;空间分布丰要旱现北部内陆地区多、南部沿海地区少的特点;全省雷暴集中发牛在4～10月,盛发期在5～9月;雷暴异常年5～9月平均大气环流与同期500 hPa大气环流特征的关系表现在雷暴频繁年低纬地区的位势高度距平场出现大范围的负距平.当年夏季西太平洋副热带高压较弱,位置偏东,雷暴偏少年则副高较强,脊线偏西.不稳定凶子K指数和TT指数对海南的雷暴有一定预报能力.     

气候条件对建筑施工的影响及其评价模型

季节性施工会受到外部气象条件的影响.在分析建筑施工受气象因素影响的基础上,建立了模糊层次综合评价模型.利用该模型,可对建筑工程施工时受不利气象条件影响程度做出预先评价,从而合理安排季节性施工.     

Characteristics and Changes of Cold Surge Events over China during 1960-2007

This paper demonstrates regional characteristics, a long-term decreasing trend, and decadal variations in the frequency of cold surge events based on daily mean temperature and daily minimum temperature data in mainland China from 1960 to 2008. During these 48 years, four high frequency centers of cold surge events were located in Xinjiang, central North China, northeast China, and southeast China. A main frequency peak of cold surge events occurs in autumn for the four regions and another peak is detected in spring over northeast China and southeast China. The regional pattern of cold surge frequencies is in accordance with the perturbation kinetic energy distribution in October-December, January, and February-April. The long-term decreasing trend （-0.2 times/decade） of cold surge frequencies in northeast China and decadal variations in China are related to the variations of the temperature difference between southern and northern China in the winter monsoon season; these variations are due to the significant rising of winter temperatures in high latitudes.     

厄尔尼诺和拉尼娜事件与曲江汛期旱涝和冬季冷暖的统计关系分析

本文通过制作曲江汛期旱涝指数和冬季冷指数，从强度方面简要地分析厄尔尼诺和拉尼娜事件与曲江汛期旱涝和冬季冷暖的统计关系。从而为当地的气候分析预测提供一定的参考依据。     

Preface to the Special Issue on Extreme Cold Events from East Asia to North America in Winter 2020/21

Along with anthropogenic global warming,the Northern Hemisphere(NH)has experienced more frequent cold air out-breaks and heavy snowfalls in recent decades(Petoukhov and Semenov,2010;Liu et al.,2012;Cohen et al.,2014;2020;Overland et al.,2015).The most recent example of extreme winter weather was the extreme cold events that occurred from East Asia to North America during the winter of 2020/21(Cohen et al.,2021;Zheng et al.,2022a).     

Prediction of Changes in Soil Moisture Associated with Climatic Changes and Their Implications for Vegetation Changes: Waves Model Simulation on Taihang Mountain, China

The WAVES model was used to simulate the effect of global warming on soil moisture on the semi-arid Taihang Mountain in China. Parameters of the WAVES model were first adjusted according to soil moisture data from a field global warming experiment. Then, the reliability of WAVES in predicting soil moisture changes induced by climatic change was confirmed by comparing the simulated and observed soil moisture values under different climatic conditions and plant growth rates of another field treatment. Next, 10 climate change scenarios incorporating increases in temperature and changes in precipitation were designed. When a simulation was conducted using the leaf area index (LAI) growth pattern from a field experiment under the present climatic conditions, the results suggested that the combination of temperature increase and precipitation decrease would greatly decrease soil water content throughout the entire simulation period. On the other hand, only when precipitation increased by 20% and temperatureincreased by 2 °C, the effect of precipitation increase on soil moisture was obviously positive. Although soil moisture conditions in the T2P1 (temperature increase by 2 °C and precipitation increase by 10%) and T4P2 (temperature increase by 4 °C and precipitation increase by 20%) scenarios were slightly better during the rainy season and notmuch changed before the rainy season, the positive effect of 10%precipitation increase on soil moisture was totally offset by moisture decrease caused bya 4 °C temperature increase in the T4P1 scenario. At the same time, the trends of soil-moisture change were highly coincident with predicted changes in productivity. Finally, the predicted LAI values from other studies were combined with the climatic change scenarios and used in the simulation. The results showed that changes in LAI alleviated, at least to some extent, the effects of temperature and precipitation changes on soil moisture.